SOME DEDUCTIONS FROM THE EXTREMUM PRINCIPLES FOR NON-NEWTONIAN FLUIDS

Abstract

A few new inequalities giving estimates for a drag force and so on are obtained. Furthermore, the following proposition is proved theoretically by means of the variational principles in a few special cases: The drag force on a body moving slowly with a constant velocity through a fluid with a given viscosity is smaller than the drag force on the same body moving with the same constant velocity through another fluid with higher viscosity. This proposition yields the conclusion that the Ostwald - de Waele fluid model is not so suitable for use in the analysis of the creeping flow of a polymer solution past a body.